Grinding or polishing wheel.



Patented Feb. 6, |900.

J. F. SPHN.

GRINDING 0R POLISHING WHEEL.

(Application flied (Nu Model.)

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JOSEPH F. SPOHN, OF SORANTON, PENNSYLVANIA.

GRINDING OR POLISHING WHEEL.

SPECIFICATION forming part of Letters Patent No. 642,828, dated February 6, 1900.

Application filed July 17,1899. Serial No. 724,155. (No model.)

T0 all whom it 11i/ty 0072.067172.:

Be it known that I, JOSEPH F. SPOHN, a citizen of the United States, residing at Scranton, in the county of Lackawanna and State of Pennsylvania, have invented certain new and useful Improvements in Grinding or Polishing Wheels, of which the following is a speciiication.

My invention comprises certain improvements in composite grinding and polishing wheels, such as emery and corundum wheels, whereby a safe and strong wheel is provided. lVhen wheels of this character burst from centrifugal force, the lines of fracture almost invariably extend from the center to the circumference, and in order to prevent serious accidents from the flying fragments of the wheel it is customary to form the wheels with shoulders upon the sides or with convex or tapering sides and to provide safety-collars fitting over said sides to retain the parts of the wheel after the fracture has taken place. Such devices do not materially strengthen the wheel and prevent fracture, but merely prevent the parts froml iiying asunder afterl the fracture occurs. By my improvements the wheel is strengthened so as to resist bursting strains, and the parts of the wheel in the event of a fracture are restrained from being thrown off by centrifugal force.

In order to make my invention clear, Ishall in the following specification describe the method of making the wheel and the wheel itself.

In the accompanying drawings, which illustrate my invention, Figure 1 is a sectional view through a mold, illustrating the method of making the wheels. Fig. 2 is a perspective view of one-half of a wheel made in accordance with my invention. Figs..3, 4, and 5 are similar views of modifications; and Fig. 6 is a perspective view of the disk, which is shown as embedded in the wheel illustrated in Fig. 2.

In Fig. 1 of the drawings, which is illustrative of the method of manufacturing my improved grinding-wheels,1 represents in section a circular mold in which are placed removable metallic linings 2 and 3 to prevent the material f1 from which the wheel is made from sticking to the bottom and side of the mold. In the center of the mold is an upright rod 5, adapted to receive a removable or shoulder 8 on one side, and aface 9, tapering from the inner edge of the shoulder to the periphery, is placed with its flat side down upon the bottom lining of the mold, the central opening 10 passing over the bushing t3. The plastic mass 4, consisting ofv emery, corundum, or other abrading material and a binding material, such as silicate of soda, which becomes set when heated, is emptied into the mold and firmly packed with suitable camping-tools. Aremovablelining-diskllis then placed upon the top surface of the mass and a heavy pressure-plate 12 is laid upon said lining. Pressure is applied tothe plate 12 by means of a clamping-plate 13, having an annular flange 14, which fits inside of the mold and rests upon the pressure-plate, and a set of clamping-bolts 15, which pass through openings in the projecting portions 16 and 17 of the clamping-plate and mold, respectively, said bolts being provided with suitable nuts 18. By turning the n uts 18 a heavy pressure is applied to the mass of material f1, making it as compactas possible. The moldis then placed in an oven and heated. Under the iniiuence of the heat the disk 7 expands, enlarging the space inclosed by the ring 8, and by reason of the pressure which is constantly applied more of the plastic material is forced into the space inclosed by the iiange as the latter eX- pands. After the mold has been in the oven a sufficient length of time the moisture is entirely expelled from the binding material and the mass becomes set and hardened. The

mold is then taken from the oven and allowed to cool. In cooling the disk shrinks to its normal size and the annular shoulder or ring 8 shrinks upon the hub-like section of the grinding-wheel contained within said ring. The grinding material also shrinks somewhat in cooling, but not to as great an extent as the metal disk. Fig. 2 is a section through a Wheel thus made when removed from the mold after cooling and fitted with the usual lead bushing 19. It will be seen that the disk is embedded in the wheel and becomes a partthereof. The ring or shoulder strengthens the cen- IOO tral part of the Wheel by binding it in with great force, thereby preventing breakage to a large extent, and should a fracture occur the ring will prevent the parts from being thrown off by centrifugal force.

Instead of forming the Wheel with a disk having a ring-flange embedded in it, as shown in Fig. 2, it may be formed in asimilar manner with simply a ring 20, as shown in Fig. 3, the disk being omitted. I prefer to bevel the inner sides 9 of the rings and to make them comparatively Wide, so as to obtain the greatest strength with the least amount of metal, the ring thus formed having a cross-section tapering from the interior face to the periphery. I may, however, use rings rectangular in cross-section, as shown in Fig. 5, or of any other suitable cross-section.

In som e instances,in the case of large wheels, it may be desirable to em bed in the wheel two or more rings, one of which may be formed upon adisk, as shown in Fig. L L. Several light rings may be embedded in the wheel on one or both sides, giving the required strength without setting very deeply into the body of the material. Where several concentric rings are thus employed, the outer rings may be removed in succession as the grinding material wears away until only the innermost ring remains, when the wheel may be considered as Worn out.

In case of fracture of the wheel from the center the usual washers, which are placed upon the arbor of the grinding-Wheel, (indicated in dotted lines, Fig. 5,) will hold the parts in line, and the ring or rings upon the side will prevent the parts from dying outward, so that ordinarilyit is not necessary to have the rings at any other place than upon one side.

It Will be seen that by means of my improvements a safe and economically-constructed Wheel is provided which does not require safety-collars or other auxiliary safety devices.

IIaving described my invention, What I claim, and desire t0 secure by Letters Patent of the United States, is

1. A grinding or polishing wheel consisting of a mass of abrading and binding material and a metal ring, said ring being embedded in the mass and shrunk onto the center or hub during the process of forming the Wheel.

2. A grinding or polishing Wheel consisting of a mass of abrading and binding material and a metal ring, said ring being embedded in the side of said mass and shrunk onto the center or hub during the process of forming the wheel, and having a cross-section tapering from the interior face of the ring to its pcriphery.

In testimony whereof I aflix my signature in presence of two witnesses.

JOSEPH F. SPOlIN.

XVitnesses:

ROBERT WATSON, WILLIAM K. RIUHART. 

